1. Field of Invention
This invention relates generally to rotary powered lawn mowers, and more particularly to a multi-bladed, multi-level lawn mower rotor adapted to slice grass engaged thereby into small pieces which are deposited on the lawn to provide a mulch therefor.
2. Prior Art
The typical powered lawn mower cuts grass into large pieces which are deposited on the lawn. It becomes necessary, therefore, to rake and collect the grass cuttings as well as leaves fallen on the lawn and to dispose of this waste material. In some cases, the mower is arranged to draw the cuttings into a bag and thereby simplify the disposal procedure.
It is often desirable that a rotary power lawn mower be capable not only of cutting grass but also of chopping the grass clippings, leaves and other organic debris lying in the path of the mower into finely cut pieces to serve as mulch about the grass roots. By finely comminuting grass and leaves and spreading the finely cut organic material over the lawn, one not only enhances the growth conditions of the lawn, but the need for raking, collecting and disposing of grass cuttings is obviated.
To this end, the prior patent to Clark, U.S. Pat. No. 2,663,984, discloses a powered lawn mower which includes a screen disposed within the casing above the rotating sickle blade and against which the blade acts to project grass and leaf cuttings for comminution. To impel the cuttings against the screen for more effective fragmentation, the sickle is provided with fan blades.
The difficulty with the comminuting lawn mower of Clark, apart from its relative mechanical complexity is that the clippings tend to accumulate inside the blade housing and to stall the mower. Other forms of comminuting types of powered lawn mowers which suffer for similar drawbacks are disclosed in the following patents: Hass, U.S. Pat. No. 4,083,166; Anderson, U.S. Pat. No. 3,703,071, and Pursel, U.S. Pat. No. 3,797,212.